Vibration for MDs via audio-jack

[Funfinder]

Hi,

the vibration feature of the Makro Racer is absolutly fanatastic
so it would be really great to have it for other detectors, too!

Instead of the headphone a little box gets plugged in the detector
which vibrates when the detector starts to signalize a find.

The more and louder the audio-signals, the faster the motor spins.
Including variable resistor for adjusting the threshold-level.



So far I found this page:
http://electronics.stackexchange.com...h-audio-signal

Do this: NPN trans or two (wired parallel for current) Resistor for base (100 ohms or so) Pager from 5V to Collector of NPN trans (or whatever max the motor can handle) Bring Audio through diode with capacitor to smooth voltage out

The basic idea is you use the diode and capacitor to create a variable DC level in the capacitor. This charge will feed to the resistor to act as the base bias. This will allow you to use volume control to determine when the pager motor turns on or off.

Probably the energy of the audio-output is too low to drive the little vibration-motor directly.


I haven't found it so far but eventually there exists already some
external vibration-alert-device for very old cell-phones or other stuff.

I'm shure alot people would like such vibration-addon for their detectors.

[Skippy]

This kind of thing?
http://treasureproducts.com/vibraphone.html
There's mention here, too:
http://www.easytreasure.co.uk/hoh.htm

[Funfinder]

Thanks for the info - the first link - Vibra-Phone 280 - looks pretty good
but a little bit expensive and I wonder why they write:
"Vibra-Phone works with most all common detector models except Minelab and Fisher"

Huh? Such a device should work with all detectors!


btw. I hope that all waterproofed diving detectors have this feature by standard
so no disturbing headphones are needed.


Meanwhile I've found out that the Makro Racer's vibration-motor works with ca. 4v DC
at full speed and if all those motors work with DC it's no prob to built some amp-circuit.

First I have to check from what working or broken device I can rip such motor and then
the tinkering can start. Keep ya informed.

[Skippy]

It probably doesn't work with detectors that use 'ring & tip' for audio, it only suits 'Ground & (ring+tip together)' machines. I think older Fishers use ring & tip. New models like the F75 use ground & ring+tip.

[Funfinder]

Since 2 days I'm experimenting - with 2 stage transistor amp and LM358 op-amp it does not work.

Using some with already 1,2v spinning Deteknix Pinpointer vibration-motor.

If internally at MD side (or mp3 player etc.) the ground is connected with audio-out its a problem
(if there is always a very weak current flow even if there is no audio-output at all)
and the very weak frequency spikes are not directly amplified from totally 0v to 1v or something.

But I'm coming closer:
The keywords for search are: "convert audio to voltage"

Here some links:
http://www.avrfreaks.net/forum/how-c...io-signal-0-5v
http://www.edaboard.com/thread172642.html

Next time I'll use some field effect op-amp because the audio-amplitudes
create weak voltage peaks (depending on the volume around 0,2 - 0,6v).

Or it works with rail-to-rail op-amps like the AD8691, 8692 & 8694.


The main tinkering will be to set the amplification exactly on a level where
low signals are still not causing enough amplification output while only a
tiny bit louder ones will create 1,2v or more so the vibration-motor spins.
Some trim-pot may help.

[Funfinder]

here it is: Audio to vibration circuit!

Good news!

Today I was successful in creating that circuit.

All whats needed is a common LM358N op-amp and a few resistors!
It works already with pretty quiet audio-output from some not very
loud mp3 player - it was at volume 16 of 32 when the vibration started.

The crazy discovery:
Before it starts to vibrate the motor works as some very silent and
distorted speaker!
No joke, its possible to listen somehow to the music via mini-vibration-motor!
Because of the windings and magnets inside which work like an usual speaker.

However this circuit so far is not perfect even if it works already
fantastic to convert not amplified audio-out signals into vibration.

If the audio is not connected it vibrates by itself all the time as long as there
is not some 100k resistor connected between non-inverted input A and ground.
But this reduces sensitivity alot (50%).

And it doesn't work with all audio-devices because then it vibrates
even if the audio is completly silent.
Hopefully I'll will find out what's the reason for that
but so far I'm enjoying my little cool invention anyway.
Schematic will follow and perhaps its already clear for the experts here
how it works.

The pinpointer is not connected, only the vib-motor of it,
the diode is not needed and instead of the 47ohm resistor
also 10ohm works which makes the circuit even more sensitive.

If you have any improvement ideas you're welcome.


Enjoy!

[Funfinder]

Audio to vibration circuit schematic!

Enjoy the schematic!

audio_to_vibration_circuit_schematic.jpg

After some further experiments now the audio to vibration circuit is adjustable to
all kind of audio-out sources from very quiet to pretty loud and it does no longer
vibrates if there is no audio connected.

The audio-input is very high impedance and extremly sensitive but
also highly secured by a 470k resistor so no capacitor there is needed.
It should work for every metal-detector and without additional amplifier!

It also works with smart-phones and all kind of audio-devices,
when you need some vibration-alert if an audio-signal occures.

Maybe it even works with microphone input, not tested yet.

Enjoy the Makro Racer search experience without Racer!

This vibration-circuit is an exclusive release for geotech-forums!

It can save you alot money and its not shure that such a special device is available at all...
The needed parts even can be found on the PCBs from broken devices or pinpointers etc.

Good luck!

[Funfinder]

Vibration-circuit for metal-detectors schematic [super high sensitivity version!]

audio_to_vibration_circuit_-_high_sensitivity_-_schematic.jpg

[Funfinder]

little error corrected - more info here:

http://www.geotech1.com/forums/showt...231#post207231

audio_to_vibration_circuit_-_high_sens!_-_schematic.jpg

[Funfinder]

After testing the circuit with non-motion and motion-detectors I found out the
vibration-contrast is too small.

I have changed it - meanwhile it vibrates 1.) already even if the
audio is connected without ground (high amplified EM-field signals)
and 2.) if I connect 2 contacts with a dry shirt!
(because of additional transistor some ca 5.000.000 ! ohm resistor is
enough to start the vibration from quiet to full)

At the moment I'm not shure whats the best to do:
A circuit that only reacts when special audio-frequencies are present
or some opamp comparation where the exact window-values from the
low voltage audio-output power are selectable.
High sensitive so it doesn't vibrates on erratic noise but already
starts if some just very bit louder or longer signal occures.
For non-motion-MDs or PI audio output it's alot easier.


This stuff is more complicated than I ever had imagined!
My respect to the Makro engineers how good they have solved it!
In all metal mode even very small coins at high mineralized soil
with the 40cm coil give a very clear vibration signal.
Not too short, not too long, really just perfect and also still great
working with very high sensitivity settings where some background
noise can occure.

If you can grab directly the digital converted detection signals, starting
the vibration and selecting the signal-level is easy (like also Pinpointers do),
but not with the everywhere slightly different analog audio-output.
My experiments will go on and any ideas are welcome.

[Skippy]

Quote:"My respect to the Makro engineers how good they have solved it!"
They are not driving the vibe-motor from the audio, they are devising their own independant drive, probably involving software timing. And they are not designing a "Universal" vibe system, either, just one that works in their own machine.
Your quest to make a Universal system is made much more difficult due to different machines having different output characteristics. Some are variable amplitude, some use PWM methods to achieve the different volume levels. Also, audio levels vary over a much wider range than the vibe motor can reproduce.
If you want to experiment further, I suggest you look into monostable timers to drive your motor. Find the minimum On-time that gives a worthwhile spin of the motor, choose a sensible maximum On-time (250 msec?), then come up with a timer that is triggered when the audio is above a threshold level, and it's time duration is determined by the strength of the audio signal. It might be worth simplifying the timer control to one of 3 or 4 different durations, eg. by switching in fixed resistors on the timer circuit. Alternatively, have a short-duration timer (50 msec?) and keep retriggering it if the audio is still present, with an overall limit of 250 msec.

On the subject of vibe motors, it may be worth considering the ones that are used in "rumble pack" video-game controllers (Playstation, Nintendo etc). Some of these handsets can be obtained for virtually nothing at Flea markets/garage sales/jumble sales/car boot sales etc.
I suspect they will be sloooower than the tiny phone ones, but obviously stronger in action.

[Funfinder]

The timing method would be great to start the motor only if the audio signal
has a certain lenght. Those most of the time worthless erratic noises are
extremly short, perhaps 0,01 to 0,05 seconds.

Fainting signals may start from 0,1 second and real good ones may give some 1sec beep.
Motion detector signals - the non-motion beeps all the time as long as the metal is present.


Don't know how good it works but because I had already half success to
make the Blisstool vibrate when a real good find-signal occured while
the vibes were much weaker without such signal my new idea is to regulate
the already by transistor amplified audio-level that comes from the MD
by some variable resistor.

The audio-out of any MD first will be amplified by a factor of 10 to 100
(have to test this first) and afterwards this amplified signal that
switches the op-amp on or off will be
adjustable by a trim poti from 100% to 1% or even smaller.
This should make it shure that it works with any MDs, very quiet
or super loud ones - any time adjustable by varible resistor.

The best method would be to make any audio signal completly even
and afterwards spreading the whole volume spectrum from 0 to 1000.
But its not shure it works because it depends how high is the volume
of the erratic background noise. If its the same loud as good signals
it may not work or this ultra-short noises have to be blurred or
filtered out.

The most easy way first is to make non-motion detectors
or P.I.s vibrate because they just have audio on or off.
No matter how loud or quiet is their audio-output, after amplification
it's loud enough and can be re-adjusted if it should be too loud.

This is the first step. Per instance if the non-motion Jeohunter beeps,
the vibration-motor should start. With my first circuit is was not
the case but I'm pretty shure that now with the additional
and adjustable transistor-stage it will.

Next the correct limit and exact volume for motion-signals
has to be found. Of course this is very simple - just set the
motion detector to lower sensitivity so no more erratic noise
exists - just clear 0,5 - 1sec beeps.

Of course seen professional it should vibrate also at very high
sensitivity - but only if the signals are good or long enough.

And it would be even better if the vibration acts the same as
it does with my sensitivity-limit modded Garrett Pro-Pointer:
Very slow and soft if the signals are very weak and real powerful
if it receives the full detection level.


However - what's really important is that detection by vibration
with an usual MD only will be a professional alternative if it works
really sensitive. Otherwise too many finds could not be detected.
With a trained ear together with repeating sweeps even smallest
changes or identical signal-patterns can be "read" which a rookie
just would interprete as "erratic noise".

And also different audio-tune-signals for different sorts of metal
will be hard to rebuilt just by different vibration-patterns.

But on the other hand detecting by vibration while listening
to music etc. can make the whole task much more interesting
and motivating - especially very long or extensive searches at
boring regions.


At the moment the status quo is:
The vibration circuit works - but how high sensitive
in terms of metal detection depth etc. we can get it... ?

[Funfinder]

Two interesting solutions haven't been mentioned so far:

1.
Using some at least 3 way light-organ circuit for intermediate signal processing.

Light-organs have a very high reaction speed and even an ultra short bass-beat
will cause already some light flash.

With such a circuit it's also possible to create different vibration patterns for
3 tone audio metal-detectors where a high sound represents noble metal etc.
and it's possible to adjust the still recognized signal-peaks lenght.


Attached are the audio captures of the Makro Racer with 40cm coil at higher
e-smog level incl. some usual detection signals which shows pretty good the
signal situation which an audioplug vibration circuit should be able to handle.



The 5sec mp3 is the recorded audio-output and the pix show the short timings.

One erratic-noise cycle lasts 0,002sec (2msec) with amplitude peak of ca. 0,5msec.
A find signal is exactly 100 millisec. long. Compared with alot other motion-detectors
there is not much difference.

2.
So what's needed is a circuit that is adjustable to those louder find-signals
from ca. 75 msec to 200 msec using a timing-window for motion-metal-detectors.
The ultrafast and thinned erratic noise this way can be ignored completly.

If a signal with a certain power level lasts for a pre-adjustable time the vibration
starts while otherwise the motor remains silent.

[Funfinder]

I have found now the solution:

OhMiBod Club Vibes 2

https://www.youtube.com/results?sear...y=ohmibod+club

When while tipping the silver-dollars ring, the webcam girls get a good vibration!

Pretty the same as while treasure-hunting!

Attach the audio part near the speaker of the MD and the vibration part in your
trouser-pocket and not in your underpants - because you have no time for sex!

Afaik it even has different vibration patterns caused by different audio-signals.
So even the discrimination might work. Some girls also use it for the disco.

Technically spoken it's a tool for cyber-sex or an orgasm-remote-control.
https://www.youtube.com/results?sear...bod+chaturbate

But it seems the batteries could be the problem.
The vibrator has an internal LiPo accu which has to be recharged pretty
often (over USB) while the transmitter needs a special small 12v battery.
http://ohmibod.org/batteries-12v-bli...-346-p686.html

The weight is not that much. It has different microphone sensitivity settings
and the vibration pattern also is adjustable. All what makes a girl happy!

The transmitter has an around 7 meter range but the question is:
Does it distorts the MD or not? Its at 434 MHz.

Price: ca. 65 dollars:
http://www.ebay.com/sch/Sex-Toys-/17...&Brand=Ohmibod

Here are the technical details:
http://www.ohmibod.com/customer-care...b-vibe-2oh.pdf

[bernte_one]

solution from Eddy71
http://smartelectronix.biz/publ/plat...telja/1-1-0-76